From 975495acd8175b9d6cb67c3802b2e90e620ccd32 Mon Sep 17 00:00:00 2001
From: Paul Gschwendtner <paulgschwendtner@gmail.com>
Date: Sat, 9 Jul 2016 00:20:23 +0200
Subject: [PATCH] feat(slide-toggle): add drag functionality to thumb

---
 src/components/slide-toggle/slide-toggle.html |   8 +-
 src/components/slide-toggle/slide-toggle.scss |   6 +
 src/components/slide-toggle/slide-toggle.ts   | 107 +++++++++++++++++-
 src/core/gestures/MdGestureConfig.ts          |  40 +++++--
 test/karma.config.ts                          |   1 +
 5 files changed, 145 insertions(+), 17 deletions(-)

diff --git a/src/components/slide-toggle/slide-toggle.html b/src/components/slide-toggle/slide-toggle.html
index 80312ea02f33..3672e96da704 100644
--- a/src/components/slide-toggle/slide-toggle.html
+++ b/src/components/slide-toggle/slide-toggle.html
@@ -1,7 +1,13 @@
 <label class="md-slide-toggle-label">
+
   <div class="md-slide-toggle-container">
     <div class="md-slide-toggle-bar"></div>
-    <div class="md-slide-toggle-thumb-container">
+
+    <div class="md-slide-toggle-thumb-container"
+         (slidestart)="_onDragStart($event)"
+         (slide)="_onDrag($event)"
+         (slideend)="_onDragEnd($event)">
+
       <div class="md-slide-toggle-thumb">
         <div class="md-ink-ripple"></div>
       </div>
diff --git a/src/components/slide-toggle/slide-toggle.scss b/src/components/slide-toggle/slide-toggle.scss
index a02ca683c188..a0c4f0133384 100644
--- a/src/components/slide-toggle/slide-toggle.scss
+++ b/src/components/slide-toggle/slide-toggle.scss
@@ -129,6 +129,12 @@ $md-slide-toggle-margin: 16px !default;
 
   transition: $swift-linear;
   transition-property: transform;
+
+  // Once the thumb container is being dragged around, we remove the transition duration to
+  // make the drag feeling fast and not delayed.
+  &.md-dragging {
+    transition-duration: 0ms;
+  }
 }
 
 // The thumb will be elevated from the slide-toggle bar.
diff --git a/src/components/slide-toggle/slide-toggle.ts b/src/components/slide-toggle/slide-toggle.ts
index ea66875bdfe1..d103c2b6530d 100644
--- a/src/components/slide-toggle/slide-toggle.ts
+++ b/src/components/slide-toggle/slide-toggle.ts
@@ -7,14 +7,16 @@ import {
   Input,
   Output,
   EventEmitter,
-  AfterContentInit
+  AfterContentInit,
+  ViewChild
 } from '@angular/core';
 import {
   ControlValueAccessor,
   NG_VALUE_ACCESSOR
 } from '@angular/forms';
-import { BooleanFieldValue } from '@angular2-material/core/annotations/field-value';
-import { Observable } from 'rxjs/Observable';
+import {BooleanFieldValue} from '@angular2-material/core/annotations/field-value';
+import {Observable} from 'rxjs/Observable';
+import {applyCssTransform} from '@angular2-material/core/style/apply-transform';
 
 export const MD_SLIDE_TOGGLE_VALUE_ACCESSOR: any = {
   provide: NG_VALUE_ACCESSOR,
@@ -58,6 +60,13 @@ export class MdSlideToggle implements AfterContentInit, ControlValueAccessor {
   private _hasFocus: boolean = false;
   private _isMousedown: boolean = false;
   private _isInitialized: boolean = false;
+  private _domRenderer: MdSlideToggleRenderer = null;
+
+  // Drag pointer, which holds information about the current drag.
+  private _dragPointer: {
+    barWidth: number;
+    percentage?: number;
+  };
 
   @Input() @BooleanFieldValue() disabled: boolean = false;
   @Input() name: string = null;
@@ -74,6 +83,7 @@ export class MdSlideToggle implements AfterContentInit, ControlValueAccessor {
 
   constructor(private _elementRef: ElementRef,
               private _renderer: Renderer) {
+    this._domRenderer = new MdSlideToggleRenderer(this._elementRef);
   }
 
   /** TODO: internal */
@@ -95,7 +105,8 @@ export class MdSlideToggle implements AfterContentInit, ControlValueAccessor {
     // emit its event object to the component's `change` output.
     event.stopPropagation();
 
-    if (!this.disabled) {
+    // Once a drag is currently in progress, we do not want to toggle the slide-toggle on a click.
+    if (!this.disabled && !this._dragPointer) {
       this.toggle();
     }
   }
@@ -202,6 +213,7 @@ export class MdSlideToggle implements AfterContentInit, ControlValueAccessor {
     }
   }
 
+  /** Emits the change event to the `change` output EventEmitter */
   private _emitChangeEvent() {
     let event = new MdSlideToggleChange();
     event.source = this;
@@ -209,6 +221,93 @@ export class MdSlideToggle implements AfterContentInit, ControlValueAccessor {
     this._change.emit(event);
   }
 
+
+  /** @internal */
+  _onDragStart() {
+    if (this._dragPointer) {
+      return;
+    }
+
+    let thumbBarRect = this._domRenderer.getThumbBarClientRect();
+    let thumbRect = this._domRenderer.getThumbClientRect();
+
+    this._dragPointer = {
+      barWidth: thumbBarRect.width - thumbRect.width
+    };
+
+    this._domRenderer.toggleDragging(true);
+  }
+
+  /** @internal */
+  _onDrag(event: HammerInput) {
+    if (!this._dragPointer) {
+      return;
+    }
+
+    let barWidth = this._dragPointer.barWidth;
+    let distance = Math.max(-barWidth, Math.min(event.deltaX, barWidth));
+
+    let percentage = (distance / barWidth) * 100;
+
+    if (percentage < 0) {
+      percentage += 100;
+    }
+
+    this._domRenderer.updateThumbPosition(percentage);
+    this._dragPointer.percentage = percentage;
+  }
+
+  /** @internal */
+  _onDragEnd() {
+    if (!this._dragPointer) {
+      return;
+    }
+
+    this.checked = this._dragPointer.percentage > 50;
+
+    this._domRenderer.updateThumbPosition(null);
+    this._domRenderer.toggleDragging(false);
+
+    // We have to clear the drag after one tick, because otherwise
+    // the click event will fire and toggle the slide-toggle again.
+    setTimeout(() => { this._dragPointer = null; }, 0);
+  }
+
+}
+
+/**
+ * Renderer for the Slide Toggle component, which separates DOM modification in it's own class
+ */
+export class MdSlideToggleRenderer {
+
+  constructor(private _elementRef: ElementRef) {}
+
+  getThumbClientRect(): ClientRect {
+    let thumbEl = this._elementRef.nativeElement.querySelector('.md-slide-toggle-thumb-container');
+    return thumbEl.getBoundingClientRect();
+  }
+
+  getThumbBarClientRect(): ClientRect {
+    let thumbBarEl = this._elementRef.nativeElement.querySelector('.md-slide-toggle-bar');
+    return thumbBarEl.getBoundingClientRect();
+  }
+
+  /**
+   * Updates the thumb containers position by using the specified percentage.
+   * When the percentage is set to `null`, the custom thumb position will be removed.
+   */
+  updateThumbPosition(percentage: number) {
+    let thumbEl = this._elementRef.nativeElement.querySelector('.md-slide-toggle-thumb-container');
+    applyCssTransform(thumbEl, percentage === null ? '' : `translate3d(${percentage}%, 0, 0)`);
+  }
+
+  /** Toggles the dragging class for the thumb container to toggle the transition duration. */
+  toggleDragging(isDragging: boolean) {
+    let thumbEl = this._elementRef.nativeElement.querySelector('.md-slide-toggle-thumb-container');
+    thumbEl.classList.toggle('md-dragging', isDragging);
+  }
+
+
 }
 
 export const MD_SLIDE_TOGGLE_DIRECTIVES = [MdSlideToggle];
diff --git a/src/core/gestures/MdGestureConfig.ts b/src/core/gestures/MdGestureConfig.ts
index b7edb49af989..85d35437485a 100644
--- a/src/core/gestures/MdGestureConfig.ts
+++ b/src/core/gestures/MdGestureConfig.ts
@@ -4,6 +4,7 @@ import {HammerGestureConfig} from '@angular/platform-browser';
 /* Adjusts configuration of our gesture library, Hammer. */
 @Injectable()
 export class MdGestureConfig extends HammerGestureConfig {
+
   /* List of new event names to add to the gesture support list */
   events: string[] = [
     'drag',
@@ -12,6 +13,11 @@ export class MdGestureConfig extends HammerGestureConfig {
     'dragright',
     'dragleft',
     'longpress',
+    'slide',
+    'slidestart',
+    'slideend',
+    'slideright',
+    'slideleft'
   ];
 
   /*
@@ -29,22 +35,32 @@ export class MdGestureConfig extends HammerGestureConfig {
   buildHammer(element: HTMLElement) {
     var mc = new Hammer(element);
 
-    // create custom gesture recognizers
-    var drag = new Hammer.Pan({event: 'drag', threshold: 6});
-    var longpress = new Hammer.Press({event: 'longpress', time: 500});
+    // Create custom gesture recognizers
+    let drag = this._createRecognizer(Hammer.Pan, {event: 'drag', threshold: 6}, Hammer.Swipe);
+    let slide = this._createRecognizer(Hammer.Pan, {event: 'slide', threshold: 0}, Hammer.Swipe);
+    let longpress = this._createRecognizer(Hammer.Press, {event: 'longpress', time: 500});
+
+    let pan = new Hammer.Pan();
+    let swipe = new Hammer.Swipe();
 
-    // ensure custom recognizers can coexist with the default gestures (i.e. pan, press, swipe)
-    var pan = new Hammer.Pan();
-    var press = new Hammer.Press();
-    var swipe = new Hammer.Swipe();
-    drag.recognizeWith(pan);
-    drag.recognizeWith(swipe);
+    // Overwrite the default `pan` event to use the swipe event.
     pan.recognizeWith(swipe);
-    longpress.recognizeWith(press);
 
-    // add customized gestures to Hammer manager
-    mc.add([drag, pan, swipe, press, longpress]);
+    // Add customized gestures to Hammer manager
+    mc.add([drag, slide, pan, longpress]);
+
     return mc;
   }
 
+  /** Creates a new recognizer, without affecting the default recognizers of HammerJS */
+  private _createRecognizer(type: RecognizerStatic, options: any, ...extra: RecognizerStatic[]) {
+    let recognizer = new type(options);
+
+    // Add the default recognizer to the new custom recognizer.
+    extra.push(type);
+    extra.forEach(entry => recognizer.recognizeWith(new entry()));
+
+    return recognizer;
+  }
+
 }
diff --git a/test/karma.config.ts b/test/karma.config.ts
index bf57e4a2a8e7..4ecdfd7a8070 100644
--- a/test/karma.config.ts
+++ b/test/karma.config.ts
@@ -20,6 +20,7 @@ export function config(config) {
     ],
     files: [
       {pattern: 'dist/vendor/core-js/client/core.js', included: true, watched: false},
+      {pattern: 'dist/vendor/hammerjs/hammer.min.js', included: true, watched: false},
       {pattern: 'dist/vendor/systemjs/dist/system-polyfills.js', included: true, watched: false},
       {pattern: 'dist/vendor/systemjs/dist/system.src.js', included: true, watched: false},
       {pattern: 'dist/vendor/zone.js/dist/zone.js', included: true, watched: false},